At present, most of the more that 600,000 tons of regulated biomedical waste generated by hospitals, laboratories, clinics and medical offices in the United States are disposed of through means of off-site incineration. Such incineration, whether on-site or off-site gives rise to problems concerning compliance with the Federal Clean Air Standards Act which, as a result, have often raised capital and operating costs associated therewith to prohibitive levels.
Accordingly, some effort has been directed toward the creation of industrial sized autoclaving. However, this approach has been questioned because it cannot be assured that steam penetration will occur throughout an entire load of medical waste, given the variables of packaging and fluid volumes which may exist within any particular batch of medical waste. Further, autoclaving does not render the medical waste unrecognizable or reduce its volume. Thusly, it is unsuitable for disposal in already overcrowded landfills.
Most importantly, the storing costs and liability have caused increasingly more health care institutions to turn away from having their waste hauled to off-site treatment. However, the problem of satisfactory means of on-site treatment, by whatever means, still exists.
Prior art approaches to medical waste fragmentation and disposal, other than the approaches of autoclaving and incineration include efforts at encapsulating the contaminated waste, typically in a thermoplastic compound. Such efforts are taught in U.S. Pat. No. 4,979,683 to Busdeker, entitled Portable Small Scale Medical Waste Treatment Machine and U.S. Pat. No. 4,992,217 (1991) to Spinello, entitled Apparatus and Method For Sterilizing, Destroying And Encapsulating Medical Implement Wastes.
There is further known in the art, a number of special purpose medical waste grinders having potential value in smaller or portable type disposal systems. Such grinding approaches are shown in U.S. Pat. No. 4,971,261 (1990) to Solomons, entitled Medical Waste Fragmentation and Disposal System, and U.S. Pat. No. 5,025,994 (1991) to Maitlen, et al, entitled Medical Waste Grinder.
The use of microwaves in the disinfecting of medical waste, which comprises one aspect of the present system, is shown, with reference to the treatment of sludge in U.S. Pat. No. 5,003,143 (1991), entitled Microwave Sludge Drying Apparatus and Method. Further, the use of microwaves in a medical disinfectant system for the treatment of medical waste exists in a system commercially available from ABB Sanitec, Inc., Division of Asea Brown Boveri, known as the ABB Sanitec Microwave Disinfection System. The Sanitec system has been used in Europe since 1984 and in the United States since 1990. The Sanitec system employs two basic steps--the first that of shredding the medical waste and the second that of steam-treating the ground waste while exposing the same to microwaves.
The Sanitec system suffers from a number of problems that have limited its use in the United States. One of these is that many states do not permit infectious waste to be ground prior to treatment because such grinding creates an additional risk of exposing hospital workers to infection. It is asserted by many state regulators that when medical material containing infectious agents are manipulated and disrupted, such waste, particularly waste containing aerosols, containing micro-organism are released, people can become infected through the mouth, nose and eyes as well as transdermally. A second difficulty with the Sanitec system is that its normal operating temperature, in the microwave portion thereof, is that of 203 degrees Fahrenheit. This specialists in the applicable field (which is known as epidemiology), have asserted is inadequate to confidently kill the test organism Bacillus strarochermophilus. Accordingly, the prior art of medical waste disposal and disinfection systems which employ microwaves have suffered from problems at the input stage regarding the possible release of infectious agents during the grinding step and, as well, at the output thereof because of inadequate temperature.
The instant invention addresses the above shortcomings of microwave and other prior art approaches of to medical waste disposal. In so doing there is provided a system concept applicable to various sized system including one that can easily be used within most doctors offices and, one that can be used on-site at a hospital and, finally, an industrial sized system which can be used off-site at designated medical waste disposal locations.